The present invention relates to a new and improved construction of a dewatering apparatus for longitudinal wire papermaking machines.
Generally speaking, the dewatering apparatus for a longitudinal wire papermaking machine comprises a longitudinal wire and an additional wire guided over guide elements. The additional wire is guided conjointly with the longitudinal wire, along a section or portion of the longitudinal wire, over a domed surface. The longitudinal wire extends essentially in the same wire plane before and after the dewatering apparatus.
A papermaking machine of this type has been disclosed in the commonly assigned, copending U.S. application Ser. No. 06/321,677, filed Nov. 16, 1981. With the longitudinal wire papermaking machine described in this copending application the longitudinal wire and the additional wire are guided along a common dewatering path over a dewatering shoe arranged at the height of the wire plane within the wire loop of the longitudinal wire and over a dewatering roll arranged after such dewatering shoe in the direction of movement of the longitudinal wire downwardly out of the wire plane, and thereafter over a contact or travel surface of a deflection roll arranged within the wire loop of the additional wire back towards the wire plane, where both of the wires separate from one another. This arrangement unites the advantages of a simple construction of a longitudinal wire machine with the advantages of the particularly intensive dewatering and the improved sheet formation of a twin-wire papermaking machine, as such has been disclosed, for instance, in U.S. Pat. No. 4,176,005, granted Nov. 27, 1979.